A SiC single crystal has a high hardness, high heat resistance and high corrosion resistance, and is an extremely chemically stable compound. Moreover, SiC which is a compound semiconductor having a covalent bond has superior properties such as a twice or more larger band gap, an approximately ten times higher dielectric breakdown field strength, an approximately twice higher electron saturation velocity and an approximately three times or more higher thermal conductivity, compared to silicon (Si), so SiC has drawn attention as an effective material for a high-temperature/high-speed/high-current device or a blue light-emitting device (refer to Patent Literature 1).    [Patent Literature 1] Japanese Unexamined Patent Application Publication No. H08-139140
Moreover, a diamond single crystal has the highest mechanical strength, and is chemically and thermally stable, so in recent years, the diamond single crystal has drawn attention as a material specifically suitable for a wide band gap semiconductor substrate.